The hallmark symptoms of a sinus infection are thick, cloudy or colored nasal discharge paired with a stuffy nose, facial pain or pressure, and a reduced sense of smell. Most sinus infections start as a common cold, so the early days can feel identical to any other upper respiratory bug. The distinguishing signs tend to emerge as symptoms either persist beyond the normal cold timeline or take a turn for the worse.
The Four Cardinal Symptoms
Clinicians look for four core symptoms when evaluating a sinus infection: nasal congestion or blockage, thick nasal discharge (often yellow or green), facial pain or pressure, and a reduced or lost sense of smell. You don’t need all four to have sinusitis. A diagnosis typically requires cloudy or colored drainage plus at least one of the others, either congestion or facial pain.
Beyond these, sinus infections commonly cause headache, postnasal drip (mucus running down the back of your throat), cough, fever, and fatigue. The cough often worsens at night as postnasal drip increases when you lie down. Bad breath is another frequent companion, caused by bacteria in the trapped mucus.
Where the Pain Shows Up
Facial pain from a sinus infection isn’t random. It maps directly to which sinus cavities are inflamed, and you have four pairs of them.
- Cheek sinuses (maxillary): Pain below the eyes and across the cheeks, sometimes mimicking a toothache in the upper jaw.
- Forehead sinuses (frontal): A headache concentrated across the forehead, often worse when bending forward.
- Between-the-eyes sinuses (ethmoid): Pain behind and between the eyes, sometimes with tearing and a “splitting” headache across the forehead.
- Deep skull sinuses (sphenoid): A vague, harder-to-pinpoint pain that can be felt at the front or back of the head.
Pain and pressure typically worsen when you lean forward, because gravity shifts the trapped fluid against the inflamed walls of the sinus cavity. Many people notice it peaks in the morning after lying flat all night.
Viral vs. Bacterial: How to Tell the Difference
Most sinus infections are viral. They develop alongside a cold, peak around days three to five, and gradually improve within 10 days. You don’t need antibiotics for a viral sinus infection because it will resolve on its own.
A bacterial sinus infection is more likely in three specific scenarios:
- Symptoms last longer than 10 days without any improvement.
- Severe onset: High fever (over 102°F / 39°C) with thick, pus-like nasal discharge or intense facial pain lasting three to four consecutive days at the start of the illness.
- “Double worsening”: You start feeling better, then get noticeably worse again within the first 10 days. This pattern is one of the most reliable signals that bacteria have taken hold.
The color of your mucus alone isn’t a reliable indicator. Both viral and bacterial infections can produce yellow or green discharge. What matters more is the pattern: how long symptoms last and whether they’re improving or getting worse.
Sinus Infection vs. Allergies vs. a Cold
These three conditions share enough overlap that it’s easy to confuse them. A few key differences help sort them out.
Allergies cause watery (not thick) nasal discharge, frequent sneezing, and itchy eyes, nose, or throat. That itchiness is the biggest giveaway. Allergies don’t cause fever, and facial pain is uncommon. Symptoms also tend to follow a seasonal or environmental trigger pattern rather than a 7-to-10-day illness arc.
A common cold produces clear nasal discharge that may thicken over a few days, low-grade fever, sneezing, and a general run-down feeling. It typically improves steadily after five to seven days. Once discharge turns persistently thick and colored, congestion doesn’t budge, and facial pressure sets in past the 10-day mark, the cold has likely progressed into a sinus infection.
Sinus infections are distinguished by the combination of purulent (thick, colored) discharge, prominent facial pressure or pain, headache, and a reduced sense of smell. Sneezing is notably absent in sinus infections, unlike colds and allergies.
How Symptoms Look in Children
Children get sinus infections too, but their symptoms can be harder to spot. Kids often can’t articulate facial pressure or describe a reduced sense of smell, so the diagnosis relies heavily on what parents observe.
The most common symptoms in children are a lingering cough (present in 50 to 80 percent of cases), persistent nasal discharge (71 to 80 percent), and fever (50 to 60 percent). Facial pain is reported in only about 29 to 33 percent of pediatric cases, making it far less reliable as a signal than it is in adults. The typical presentation in younger children is a cold that simply won’t quit: nasal discharge and a cough that persist well beyond the normal 7-to-10-day window.
A more dramatic presentation, with sudden high fever, thick pus-like discharge, and facial pain, also occurs but is less common in children than the slow-burn version.
Acute vs. Chronic Sinus Infections
An acute sinus infection lasts up to four weeks and usually resolves completely. Some people get several acute episodes per year but feel perfectly fine between them, a pattern called recurrent acute sinusitis.
Chronic sinusitis is a different condition. It involves sinus inflammation lasting 12 weeks or longer, with symptoms that never fully clear between flare-ups. The same four cardinal symptoms apply, but the experience shifts. Facial pain may become a dull, constant background pressure rather than sharp or throbbing. Nasal congestion and thick discharge become a daily baseline rather than something that came on suddenly. Loss of smell can become persistent and is often the symptom that bothers people most over time. Fever and acute facial pain are actually uncommon in chronic sinusitis, which is part of why people sometimes live with it for months before seeking help.
Symptoms That Need Urgent Attention
Sinus infections rarely become dangerous, but the sinuses sit close to the eyes and brain, and infection can occasionally spread to those areas. Watch for swelling or redness around an eye, a bulging eye, difficulty moving the eye in any direction, double vision, or any change in how clearly you can see. These signs suggest the infection has moved into the eye socket, a situation that may require more than antibiotics to resolve.
A severe headache with high fever, especially in teenagers and young adults with frontal sinusitis, can signal an intracranial complication. Stiff neck, confusion, or swelling on the forehead are also warning signs. These scenarios are uncommon but require immediate evaluation, typically with imaging, because the consequences of a missed diagnosis are serious.